I have recently received additional images from a participant of the first group buy.
As previously mentioned, these manifolds are designed around G series turbochargers from Garrett and other manufacturers. Compared to previously available turbo kits, we are now able to run a reverse rotated turbocharger on USDM diver side of the engine. That allows us to tuck that turbo in, closer to the engine for superior packaging reasons, as well as eliminate 90* elbow off the compressor housing that is present in a factory configuration.
Furthermore, this is now a completely symmetrical twin turbo design. That is a very important achievement which helped even out flow from each individual exhaust port. Not only are these the best flowing log style manifolds for your Z32, but they have, by far, the lowest standard deviation of flow between all cylinders.
One of the inherent issues that VG30 was suffering from is very poor flow from cylinders 5 and 6 (back on the engine). That resulted in poor exhaust gas evacuation during exhaust stroke. As a result back cylinders run hotter, are harder to fill with air/fuel mixture and are more prone to knock. If you look at history of VG30DETT failures, in majority of cases it is bearings 5 and 6 that fail first.
High power and boost applications greatly benefit from external wastegates for more reliable and precise boost control. In the past, boost creep was a significant issue for Z32 cars running high boost levels with internal wastegates through a 5-bolt housing. I am not even going to mention 4-bolt housings here.
Polar engineering manifolds are a clean sheet design which was not limited by any relevant constraints. Of course, the manifold discharge was prioritized and all exhaust port runners were optimized to merged into it, but not much less attention was dedicated to wastegate flange. The split angle between turbine and wastegate flanges is exactly the same, which is the optimal configuration for such system. Each port has an equal access path to turbine and to wastegate. That way we reduce chances of gas reversal inside the manifold and promote even flow to that gas whether it is routed through a turbine or bled off through wastegate. This is also the first manifold that does not lock your turbochargers in a forward-facing position. You are able to tuck turbos inwards if installing engine from the top, or if you decide to run G35 series turbochargers. Even compressor housings of that huge size will not come into contact with frame rails.
The driver side is completely symmetrical to passenger. If you are familiar with Z32 in its factory configuration, it had a standard rotation turbocharger on USDM driver side which required a 90* coupler off compressor discharge. That coupler is no longer necessary since compressor discharge now points straight up just like on the passenger side of the car. Again, the more evenly we can remove exhaust gasses after every stroke, the smoother things will run, and with lower chance of inherent knock at specific cylinders.
While many other turbo kits on the market require you to rebuild half the car to complete the installation, this kit works around your car and barely interferes with all parts and systems that are already there. As you can see, you are able to use same braided oil feed lines that are available for other types of Garrett turbos. Oil drain pipes are also positioned favorably to allow the use of existing hoses. Turbos actually sit a bit higher than stock units to further promote oil drain and return to pan.
We will be seeing more details in coming weeks.